Thanks for your detail explanation, Dan. Yes I did use an auto ranging DVM I just bought as new from Sears. The only thing I can guess is that my DVM may not be able to meausure that tiny value. Otherwise I can hardly believe that a brand new front O2 sensor is bad.

Anybody fixed PO420 before??? I guess I'll end up with replacing rear O2 sensor if I have no other choice %&*!@#$!


2000 4Runner 4WD SR5 V6 Auto 16x8 Chrome Wheel, 265/70/R16 BridgeStone Duelers A/T All Terran
2009 Toyota Sienna LE V6 FWD